This invention relates to polyamine reactions and their use in preparing polyaminopolymers, particularly to preparation of certain polyaminopolymers having halohydrin or dihalo (at least one halogen on each of two adjacent carbon atoms) functionality.
Certain resins are used to improve wet strength of paper. Such resins include reaction products of certain polyamides with a halohydrin, or a precursor thereof, e.g. an epihalohydrin such as is disclosed in U.S. Pat. Nos. 2,926,116; 2,926,154; and 3,332,901. Certain of these resins are sold by Hercules Incorporated under the tradename Kymene.TM..
When epihalohydrins are used in preparing the resins, there is sometimes residual epihalohydrin, which may cause inconvenient handling procedures to avoid human contact. Use of epihalohydrin is avoided in such processes as those disclosed in U.S. Pat. Nos. 4,354,006; 4,419,498 and 4,419,500. These processes involve reacting a polyamine containing at least one tertiary amine group with an allyl halide to quaternize the amine and then reacting the quaternized product with a hypohalous acid to convert allyl substituents to halohydrin moieties. A process disclosed in U.S. Pat. No. 4,520,159 involves reacting a polyaminopolyamide with an allyl halide in aqueous medium to form allyl substituents on tertiary nitrogen atoms, then converting the allyl substituents to halohydrin moieties by reacting them with hypohalous acid at a pH of about 7. Resulting polyaminopolyamide resins, however, are found to be inferior in wet strength performance to those manufactured using epihalohydrin. Additionally, such resins contain residual unreacted epihalohydrin, various dihalopropanols, allyl halides and other by-products which entail further processing for removal. The resins are often dark in color and may require additional crosslinking agents to improve wet strength performance.
These resins are typically produced, transported and stored in aqueous solutions or slurries. The presence of water, however, results in certain undesirable deterioration.
It would be desirable to produce a polyaminopolyamide wet strength resin which contains substantially no epihalohydrin, dihalopropanols, or allyl halide. Advantageously, the resin would be low in color and have wet strength properties at least equivalent to the resins made using epihalohydrins.
Advantageously, the resin could be dried and stored substantially dry then rehydrated or redissolved and used as a wet strength resin. Transport of a dry resin would avoid transport of water. Substantial absence of water would avoid degradations or deterioration such as darkening and loss of activity or solubility associated with reactions in water.